The present invention relates to digital computers. More specifically it is a power saving method and apparatus for battery powered computers.
Reducing power consumption in any electrical device is always a desireable goal. In battery powered computers this goal takes on particular urgency. For example, most battery packs can only power a computer for a few hours of continuous use. Without the incorporation of some form of power consumption reduction mechanism, a computer powered by such a battery pack will not be useable for an entire trans-continental flight.
The simplest solution to this problem is to turn the computer off during any period of non-use. Unfortunately, this solution has a high cost in user convenience. Most computers go through a complete "re-booting" process every time power is turned off and on, the length of which process can be very annoying to the user. Additionally, the user is frequently called upon to restart his application and read from a stored file after the re-booting process is complete, all of which requires additional time. The time required for both re-booting and re-starting the programs can range from 30 seconds to several minutes. Such delays discourage the user from turning the computer off except during periods of extended non-use.
To encourage the user to turn off the computer during any period of non-use, some method or apparatus which can shut the computer down and then resume operation without requiring a re-booting process and which can return the user to exactly the same place and condition as preceded the shutdown would be very desirable.